Dual-channel lateral stiffness active hydropneumatic suspension

Abstract

The present invention discloses a dual-channel lateral stiffness active oil-gas suspension, which adopts a left-right symmetrical structure and includes: a steering wheel, an angle synchronization control valve, a stiffness synchronization control valve, a suspension cylinder, an energy accumulator, a control valve and a pipeline. The suspension cylinder includes: a piston rod, a piston, an internal control valve group, a cylinder barrel, and a sealing seat ring. The interior of the suspension cylinder includes an auxiliary oil chamber and a suspension cylinder inner chamber, and the auxiliary oil chamber is completely isolated from the suspension cylinder inner chamber. The suspension cylinder inner chamber includes a cylinder barrel inner chamber and a piston rod inner chamber, which are connected through an internal control valve group to form a suspension cylinder inner chamber system. The auxiliary oil chamber is connected to the control valve and the energy accumulator through a pipeline to form an external control loop. The angle synchronization control valve is respectively connected to the control valves of the left and right external control loops to form a state control channel. The stiffness synchronization control valve is respectively connected to the cylinder barrel inner chambers of the left and right suspension cylinder inner chamber systems to form a stiffness control channel. The two control channels and the control loops / inner chamber systems contained therein are independent of each other. The angle synchronization control valve and the stiffness synchronization control valve are synchronously controlled with the steering wheel.

Description

Technical Field

[0001] This patent relates to a vehicle active suspension structure, specifically a dual-channel lateral stiffness active oil-gas suspension. Background Art

[0002] 1. Active and semi-active suspension

[0003] The suspension is an important part of the vehicle chassis. It is located between the frame and the axle. It undertakes the chassis's buffering and shock-absorbing function on the ground and has a significant impact on the vehicle's ride smoothness and handling stability. There are several forms of suspension, including passive suspension, semi-active suspension, and active suspension, which reflect the degree of control over the mechanical properties such as chassis posture, stiffness, and damping, as well as the vehicle's running posture. Ordinary vehicles, especially load-bearing vehicles, usually use a passive suspension structure for the chassis, with fixed stiffness and damping structures, and the vehicle's ride smoothness and handling stability are poor. With the requirements for driving quality, handling quality, transportation safety, and ride comfort, people began to put forward active control requirements for the stiffness, damping, and running posture of the suspension, and then developed semi-active and active suspension systems.

[0004] Active suspension can timely adjust the suspension's posture, stiffness and damping according to the vehicle's load-bearing state, operating state and road conditions, so that the suspension system is in the best vibration reduction state, and the vehicle will have good smoothness, stability and comfort under various road conditions. The key component of active suspension is its actuator, that is, the suspension posture, stiffness and damping system that can be adjusted and controlled.

[0005] Foreign high-end products such as sedans and passenger cars have successively developed and applied semi-active and active suspension systems. The main method is to use electronic control technology to control the stiffness and damping of the suspension. The basic carriers of the suspension are coil springs, air springs and hydraulic electronic dampers. Due to the limitations of structural form, control capacity, system cost and other factors, semi-active and active suspensions are rarely used in commercial vehicles and load-carrying transport vehicles.

[0006] 2. Hydro-pneumatic suspension

[0007] The oil-gas suspension cylinder integrates the structural principles and usage functions of air springs and hydraulic dampers, and has better mechanical properties and application range. The oil-gas suspension cylinder is filled with nitrogen and hydraulic oil. Nitrogen, as an elastic medium and energy storage medium, has variable stiffness characteristics and a larger energy storage ratio than metal elastic materials. Hydraulic oil, as a damping medium, generates damping force through the damping structure inside the suspension cylinder.

[0008] Since nitrogen is encapsulated in the cylinder structure, the oil-gas suspension cylinder has a greater working pressure and capacity than the air spring. Similar to the structure of a conventional hydraulic cylinder, the oil-gas suspension cylinder is also composed of a cylinder assembly and a piston rod assembly according to the motion relationship and installation structure. The internal volume compartment includes a rod chamber and a rodless chamber, and the piston rod is usually a hollow structure. Among them, the rodless chamber is called the suspension cylinder cavity, which is composed of the cylinder cavity and the piston rod cavity. The rod cavity is called the auxiliary oil cavity, which is an annular space surrounded by the cylinder assembly and the piston rod assembly between the side walls of the waist of the suspension cylinder.

[0009] The double oil chamber structure, the inner chamber of the suspension cylinder is used as a chamber, filled with hydraulic oil and nitrogen, also known as the oil-gas mixing chamber or mixed oil chamber. During use, the volume space of the auxiliary oil chamber changes the most, and is usually used as the source of the damping flow inside the suspension cylinder. The auxiliary oil chamber is filled with hydraulic oil, and a damping channel is provided on the side wall of the piston rod inside the chamber to connect with the inner chamber of the suspension cylinder. The oil chamber filled with only hydraulic oil is called a pure oil chamber, including a variable pure oil chamber and an immutable pure oil chamber. The variable pure oil chamber is connected with the mixed oil chamber to form a damping channel. When the suspension cylinder is compressed or stretched, the volume and pressure of the variable pure oil chamber and the mixed oil chamber change to generate damping flow. The area of ​​action of the system pressure in the suspension cylinder cavity to provide elastic force to the outside is called the pressure action area. The area that generates damping flow with the compression or extension speed of the suspension cylinder is called the damping flow area. The elastic force of the suspension cylinder is determined by the system pressure in the suspension cylinder cavity and the pressure action area. The damping flow of the system is determined by the damping flow area and the compression or extension speed of the suspension cylinder.

[0010] The three-chamber structure is to divide the inner chamber of the suspension cylinder into the inner chamber of the cylinder barrel and the inner chamber of the piston rod through a piston or valve plate structure, and a damping structure is arranged on the piston or valve plate. The auxiliary oil chamber is connected to the inner chamber of the suspension cylinder through the damping structure of the piston rod side wall.

[0011] The damping flow of the suspension cylinder comes from the volume change of the variable pure oil chamber when the suspension cylinder is compressed or stretched. The generation of damping flow must connect the variable pure oil chamber to the mixed oil chamber, or connect to the mixed oil chamber through another pure oil chamber to form a damping channel. Otherwise, the mechanical relationship inside the suspension cylinder will not hold. From the existing various suspension cylinder structures, the auxiliary oil chamber is the main source of the system damping flow, and without exception, they are all connected to the inner chamber of the suspension cylinder to form a hydraulic circuit closed to the outside.

[0012] Figures 1 to 9 , which is the main structural form of existing oil and gas suspension cylinders. Figure 1 , Figure 2 It has a single air chamber and double oil chamber structure. Figure 3 to Figure 6 It is a single air chamber and three oil chamber structure, among which Figure 6 It is a pressure compensation structure. Figure 7 to Figure 9 It has a double air chamber and three oil chamber structure. Figure 7 It is a forward series structure. Figure 8, Fig. 9 It is a back pressure opposing structure.

[0013] The conventional damping structure consists of a damping hole and a one-way valve, which cannot be adjusted during use. The damping characteristic of the system is a quadratic curve F=f(v) based on the velocity term and the difference between the forward and reverse directions, see Fig.14 .

[0014] Figure 1 to Figure 7 The structure and stiffness characteristics are basically the same. For the characteristic curve, see Fig.12 , is a positive nonlinear curve with a hard point at the starting position of the curve. The entire suspension cylinder cavity system is a closed loop and cannot be controlled by external input. However, variable damping mechanism can be arranged based on the internal space and structure to achieve variable damping control to a certain extent. Fig.15 Variable damping characteristic curve.

[0015] Figure 8 , Fig. 9 As shown, although relatively good stiffness characteristics are obtained and hard points are eliminated (see stiffness characteristic curve for Fig.13 ), but these two structures must be based on the physical isolation of the cylinder cavity and the piston rod cavity, which loses the important structural, position, speed, flow and pressure relationship between the cylinder cavity and the piston rod cavity, and the complex conduit structure of the piston rod cavity occupies the internal effective space. This makes it impossible to arrange and apply the variable damping structure based on the position, flow and pressure control relationship in the suspension cylinder cavity. See Fig.11 , variable damping internal control valve group structure. In addition, the complex catheter structure of the piston rod cavity is difficult to install and maintain, and has poor reliability. The lack of external control targets and control links also makes it difficult to achieve external control of the system stiffness and state.

[0016] The existing various structures of oil-gas suspension cylinders all focus on the matching of the stiffness and damping characteristics inside the suspension cylinder itself, as well as the integrity and reliability of independent operation, without considering the setting of external input ports and internal control links for external active control. Its internal oil chamber and air chamber are interrelated and controlled with each other, and they were usually used independently as separate components before. However, as the entire chassis, especially active and semi-active suspension, active or semi-active control is required for different road conditions, operating states, and different driving and operating environments. However, the entire oil-gas suspension cylinder does not have an independent link for external control or multi-suspension cylinder combined control, so that the excellent performance and combination potential of the oil-gas suspension cylinder cannot be fully utilized. Applying external active control to the existing type of suspension cylinder structure will cause the flow and pressure inside the suspension cylinder to be disordered, leading to problems with system stability and reliability.

[0017] Active and semi-active control suspension systems require active or semi-active comprehensive control of system stiffness, damping, travel, and state. The existing oil-gas suspension cylinder basic structure lacks the structural foundation and conditions for complete realization.

[0018] Active and semi-active suspensions are widely used in high-end products such as cars and commercial vehicles. They are mainly based on the combination of leaf springs, coil springs, air springs, etc. with electronically controlled dampers, and the electronic control system is introduced for control. However, due to the problems of suspension components, working capacity, control capacity, system accuracy and cost structure of electronic control systems, the application of large vehicles and popular products is greatly restricted. The application of oil-gas suspension in engineering, heavy and special vehicles is still blank. It is urgent to propose a basic oil-gas suspension cylinder structure that can be used in active and semi-active control systems, as well as a suspension structure based on oil-gas suspension cylinders for active and semi-active control. Summary of the invention

[0019] The present invention proposes a dual-channel lateral stiffness active oil-gas suspension. Specifically, it discloses an active control based on the oil-gas suspension structure, which controls the height, stroke, stiffness, damping and other parameters of the suspension cylinder assembly through the steering wheel, so as to realize automatic matching of the roll angle, roll stiffness, roll damping with the steering angle and steering posture of the vehicle in the steering driving state.

[0020] The present invention constructs an isolated double-chamber oil-gas suspension cylinder structure. The auxiliary oil chamber is filled with hydraulic oil and is completely isolated from the suspension cylinder inner cavity. The suspension cylinder inner cavity is divided into a cylinder barrel inner cavity (pure oil chamber) and a piston rod inner cavity (mixed oil chamber) by an internal control valve group at the bottom of the piston rod. The cylinder barrel inner cavity and the piston rod inner cavity are connected through the damping channel on the internal control valve group to form a complete and independent suspension cylinder inner cavity system. The suspension cylinder inner cavity system provides the main mechanical parameters of the oil-gas suspension cylinder. The auxiliary oil chamber is connected to the control valve and the energy accumulator through the outside of the pipeline to form an independent external control loop. The external control loop forms a double-chamber back-pressure opposing structural relationship with the suspension cylinder inner cavity system through the auxiliary oil chamber. In addition to correcting and supplementing the mechanical parameters of the suspension cylinder inner cavity system, it can also implement active control of the suspension cylinder inner cavity system. See. Fig. 20 ——Isolated double-chamber oil-gas suspension cylinder structure, Fig.10 A schematic diagram of its structure is shown below.

[0021] The present invention connects and controls the external control circuits of the left / right suspension cylinders respectively through the angle synchronization control valve, forming a "state control channel" with the angle synchronization control valve as the core, controlling the oil storage in the auxiliary oil chamber of the left / right suspension cylinder, changing the stroke and height of the suspension cylinder, and then controlling the roll angle of the chassis or the upper part of the vehicle. The angle synchronization control valve is synchronized with the rotation of the steering wheel, and then controls the roll angle generated by the chassis to be synchronized with the steering angle of the vehicle, forming the best chassis steering posture. The suspension cylinder cavity system of the left / right suspension cylinders is connected and controlled by the stiffness synchronization control valve, forming a "stiffness control channel" with the stiffness synchronization control valve as the core, controlling the oil storage in the left / right suspension cylinder cavity system, and then changing the stiffness of the left / right suspension cylinder, forming the roll stiffness required by the chassis or the upper part when the chassis is turned. The stiffness synchronization control valve is also synchronized with the rotation of the steering wheel, and then controls the steering angle of the vehicle to match and synchronize with the roll stiffness generated by the chassis, forming the best chassis steering dynamics relationship.

[0022] In addition, the suspension cylinder structure constructed by the present invention completely isolates the suspension cylinder cavity system from the external control circuit and is independent of each other. It not only forms the mechanical structural relationship of the dual air chambers' counter-pressure opposition, but also maintains the complete structure of the suspension cylinder cavity and the complete association of the internal components in parameters such as position, speed, pressure, and flow. Based on this, the internal control valve group of the suspension cylinder cavity can automatically implement variable damping control of the suspension cylinder cavity system according to the changes in the pressure and stiffness of the suspension cylinder cavity.

[0023] Depending on the steering wheel turning angle and turning speed, the steering angle and turning range of the vehicle chassis form various optimal corresponding relationships with the chassis roll angle, roll stiffness and roll damping, thereby realizing active control of the operating posture and mechanical parameters of the chassis suspension system when the vehicle is turning.

[0024] The present invention adopts the following structural scheme to realize active control of suspension roll angle, roll stiffness and internal damping: a dual-channel lateral stiffness active oil-gas suspension, adopting a left-right symmetrical layout structure, including: a steering wheel, an angle synchronization control valve, a stiffness synchronization control valve, a suspension cylinder, an energy storage device, a control valve and a pipeline. Fig.21 , which is the structural diagram of the dual-channel lateral stiffness active oil-pneumatic suspension system in this example.

[0025] The left / right suspension cylinders are constructed with an isolated double-chamber oil-gas suspension cylinder structure, including: piston rod, piston, internal control valve group, cylinder barrel, and sealing seat ring. The cylinder barrel, piston rod, and piston form a suspension cylinder inner cavity (rodless cavity) inside the suspension cylinder; the cylinder barrel, sealing seat ring, piston rod, and piston form a secondary oil cavity (rod cavity) between the side walls of the waist of the suspension cylinder; the secondary oil cavity is filled with hydraulic oil and is completely isolated from the suspension cylinder inner cavity; the suspension cylinder inner cavity is divided into the cylinder barrel inner cavity and the piston rod inner cavity by the internal control valve group at the bottom of the piston rod; the cylinder barrel inner cavity is filled with hydraulic oil, and an external control interface is provided at the bottom; the piston rod inner cavity is filled with hydraulic oil and nitrogen; the cylinder barrel inner cavity and the piston rod inner cavity are connected through the damping channel on the internal control valve group, forming a complete and independent suspension cylinder inner cavity system, providing the main mechanical parameters (stiffness and damping) of the oil-gas suspension cylinder. For the auxiliary oil chamber, an external interface is set at the position of the cylinder near the sealing seat ring, and the control valve and the accumulator are externally connected through pipelines to form an independent external control loop; the control valve is provided with an external control interface; the external control loop forms a double-chamber back-pressure opposing mechanical structure relationship through the auxiliary oil chamber and the suspension cylinder inner cavity system, supplements and corrects the mechanical parameters of the suspension cylinder inner cavity system, and can implement active control by inputting external pressure and flow through the control valve. Fig. 20 , which is the isolated dual-chamber oil-gas suspension cylinder structure and basic system / circuit configuration diagram constructed in this example, Fig.10 A schematic diagram of its structure is shown below.

[0026] When the suspension cylinder is compressed or stretched, the volumes of the cylinder cavity and the auxiliary oil cavity change. For the suspension cylinder cavity system, the flow is exchanged between the cylinder cavity and the piston rod cavity, and the damping flow area is the cylinder cavity area. For the external control circuit, the flow is exchanged between the auxiliary oil chamber and the accumulator, and the damping flow area is the auxiliary oil cavity area. The total damping flow of the suspension cylinder is the sum of the damping flows of the suspension cylinder cavity system and the external control circuit. The pressure action area of ​​the suspension cylinder cavity system is the cylinder cavity area, and the pressure action area of ​​the external control circuit is the auxiliary oil cavity area. The overall elastic force output of the suspension cylinder is the superposition of the pressure of the cylinder area and the auxiliary oil cavity area. See Fig.16 ——In this example, the stiffness characteristic curve of the suspension cylinder, curve 1 is the stiffness characteristic curve of the suspension cylinder inner cavity system, curve 2 is the stiffness characteristic curve of the external control circuit, and curve 3 is the comprehensive stiffness characteristic curve of the suspension cylinder system. Fig.16 It can be seen that the external control loop has made a good correction to the stiffness characteristics of the suspension cylinder inner cavity system in the initial stage, eliminated the hard point at the starting position, and formed a bidirectional characteristic and a zero-crossing balance position.

[0027] For the external control loop, a certain pressure and flow rate are input / output on the external control interface of the control valve, which can change the pressure and oil volume in the auxiliary oil chamber, thereby changing the state, stroke and overall stiffness of the suspension cylinder. This kind of control is applied by the external control loop through the auxiliary oil chamber, which is completely isolated from the suspension cylinder internal cavity system, and is a reverse control, so it is a safe control. Fig.17 The figure shows the stiffness control characteristic diagram of the external control loop, where curve 1 is the original stiffness characteristic curve, and curve 2 is the curve of input control flow, compression of suspension cylinder height, and increase in suspension cylinder stiffness.

[0028] For the suspension cylinder cavity system, inputting / outputting a certain pressure and flow rate on the external control interface at the bottom of the cylinder can change the pressure and oil storage volume in the suspension cylinder cavity system, thereby significantly changing the overall stiffness of the suspension cylinder. Fig.18 The figure shows the stiffness control characteristic diagram for controlling the suspension cylinder inner cavity system, where curve 1 is the original stiffness characteristic curve, curve 2 is the stiffness characteristic curve after output control flow, and curve 3 is the stiffness characteristic curve after input control flow.

[0029] By combining and synchronously controlling the external control loop and the suspension cylinder internal cavity system, a variety of control effects can be achieved. Fig.19 The figure shows the stiffness control characteristic diagram for isobaric and synchronous control of the external control circuit and the suspension cylinder inner cavity system. Curve 1 is the original stiffness characteristic curve, and curve 2 is the stiffness characteristic curve after compression stroke and height reduction.

[0030] The internal control valve group is an internal pressure-controlled automatic variable damping control component. It can sense and determine the working state of the suspension cylinder according to the pressure of the suspension cylinder inner cavity system, and automatically adjust and control the flow and damping coefficient between the cylinder cavity and the piston rod cavity. Fig.15 The figure shows the damping characteristic curve of the internal control valve group which is automatically controlled according to the internal pressure of the system. Fig.11 This is a detailed structural diagram of the internal control valve group.

[0031] The angle synchronization control valve is used to connect the external control interfaces of the two external control circuits of the left / right suspension cylinders, forming a "state control channel" with the angle synchronization control valve as the core to control the two external control circuits of the left / right suspension cylinders. The stiffness synchronization control valve is used to connect the external control interfaces of the two suspension cylinder inner cavity systems of the left / right suspension cylinders through pipelines, forming a "stiffness control channel" with the stiffness synchronization control valve as the core to control the two suspension cylinder inner cavity systems of the left / right suspension cylinders. The two control channels and the control systems and circuits they contain are independent of each other to ensure the stability and reliability of the system operation. The angle synchronization control valve and the stiffness synchronization control valve are controlled synchronously with the steering wheel.

[0032] Fig.21This is the structural diagram of the dual-channel lateral stiffness active oil-pneumatic suspension system.

[0033] The "state control channel" controls the oil volume in the auxiliary oil chamber of the external control circuit of the left / right suspension cylinders through the angle synchronization control valve to change the height and stroke of the suspension cylinder, thereby controlling the roll angle and roll stiffness of the chassis to achieve posture control of the suspension.

[0034] The "stiffness control channel" controls the amount of oil stored in the suspension cylinder inner cavity system of the left / right suspension cylinders through the stiffness synchronization control valve to change the stiffness of the left / right suspension cylinders to form the required roll stiffness.

[0035] According to the control response degree of the "stiffness control channel" and the "state control channel", three control modes can be formed:

[0036] ① Under-stiffness control: The lateral stiffness trend generated by the "stiffness control channel" controlled by the "stiffness synchronization control valve" is less than the roll angle trend generated by the "angle synchronization control valve" controlling the "state control channel". At this time, the system pressure in the inner chamber of the inner suspension cylinder is greater than the system pressure in the outer chamber of the inner suspension cylinder.

[0037] ② Critical stiffness control: The lateral stiffness trend generated by the "stiffness synchronization control valve" is equal to the roll angle trend generated by the "angle synchronization control valve". At this time, the system pressure in the inner chamber of the inner suspension cylinder is equal to the system pressure in the outer chamber of the outer suspension cylinder.

[0038] ③ Over-rigidity control: The lateral stiffness trend generated by the "rigidity synchronization control valve" is greater than the roll angle trend generated by the "angle synchronization control valve". At this time, the system pressure in the inner chamber of the inner suspension cylinder is less than the system pressure in the outer chamber of the outer suspension cylinder.

[0039] Variable stiffness control is to control and change the system pressure in the suspension cylinder cavity, and the internal control valve group further automatically controls the system damping based on the system pressure in the suspension cylinder cavity, thereby establishing a basic multi-level, complete and open control architecture, which greatly enriches the methods and means of active control of oil and gas suspension.

[0040] Fig. 22 This is the system structure state diagram when the vehicle turns left. Fig.23 This is the system structure status diagram when the vehicle turns right.

[0041] When the vehicle is traveling in a straight line, the angle synchronization control valve does not actively generate control flow for the left / right external control circuits, and there is no control flow between the stiffness synchronization control valve and the left / right suspension cylinder cavity system. In the suspension cylinder cavity system, the flow is exchanged between the piston rod cavity and the cylinder cavity through the internal control valve group; in the external control circuit, the flow is exchanged between the accumulator and the auxiliary oil cavity through the control valve. When the road is bumpy, the pressure difference generated by the left / right external control circuits is cut off by the angle synchronization control valve; the stiffness synchronization control valve contains a damping cut-off valve, and the instantaneous high pressure generated between the left / right suspension cylinder cavity systems is attenuated and cut off by the stiffness synchronization control valve.

[0042] When the vehicle is turning, all systems and circuits are in working state. In the "state control channel", the angle synchronization control valve adjusts and distributes the flow of the left / right external control circuits to achieve posture control of the chassis. In the "stiffness control channel", the stiffness synchronization control valve adjusts and distributes the flow of the left / right suspension cylinder inner cavity system to achieve stiffness control of the chassis and mechanical response to the "state control channel". Under the control of different steering angles of the steering wheel, the vehicle's steering angle, roll angle, and roll stiffness form a series of corresponding states, realizing active control of the roll stiffness of the suspension system.

[0043] The core of the present invention is:

[0044] 1. Completely isolate the auxiliary oil chamber of the oil-gas suspension cylinder from the inner chamber of the suspension cylinder (including the inner chamber of the cylinder barrel and the inner chamber of the piston rod), and use the auxiliary oil chamber as the target link for external control to achieve active or semi-active control of the suspension cylinder stroke, height and stiffness;

[0045] 2. The inner cavity of the suspension cylinder, with the internal control valve group as the core connection, controls the inner cavity of the cylinder barrel and the inner cavity of the piston rod, constructs a complete pressure / flow control system, provides the main mechanical parameters (stiffness / damping) of the suspension cylinder, and realizes the variable damping active control inside the system.

[0046] 3. An energy accumulator and a control valve are installed outside the oil-gas suspension cylinder, and connected to the auxiliary oil chamber of the suspension cylinder through a pipeline to build an independent external control circuit. This achieves the following three purposes at the same time:

[0047] ① Use the accumulator (mixing oil chamber) and the auxiliary oil chamber to build a complete pressure and flow relationship of the external control circuit.

[0048] ② Use the control valve to establish an external control input port, which also serves as the damping element of the external control loop itself;

[0049] ③ The established external control circuit and suspension cylinder inner cavity system form a new and complete dual-chamber counter-pressure opposing mechanical structural relationship through the auxiliary oil cavity;

[0050] 4. The constructed external control loop is independent of the suspension cylinder inner cavity system. The mechanical parameters of the suspension cylinder inner cavity system are supplemented and corrected through the auxiliary oil cavity, and the suspension cylinder inner cavity system is actively controlled in reverse in terms of parameters such as state, stroke, pressure and stiffness.

[0051] 5. On the basis of realizing the dual-chamber back-pressure opposed structure, a complete suspension cylinder inner cavity structure is constructed to realize automatic variable damping control of the suspension cylinder inner cavity system based on the dual-chamber back-pressure opposed structure, providing a new basic architecture for various variable damping active controls in the future.

[0052] 6. Relying on the structural characteristics of the isolated dual-chamber oil-gas suspension cylinder (complete suspension cylinder cavity system and independent external control circuit), the entire suspension control system is set up in a dual-channel manner: a "state control channel" is established with the angle synchronization control valve as the core to connect and control the two external control circuits of the left / right suspension cylinder. A "stiffness control channel" is established with the stiffness synchronization control valve as the core to connect and control the two suspension cylinder cavity systems of the left / right suspension cylinder. The two control channels and the systems and circuits they contain are independent of each other to ensure the stability and reliability of the system.

[0053] A few notes:

[0054] 1. This patent builds a left / right symmetrical structure, and the entire system realizes the most complete functions and characteristics, including the reverse pressure opposing stiffness characteristics, dual system, dual channel control, variable stiffness control, variable damping control, height control, stroke control, roll angle, roll stiffness control, etc., and maintains an open structure. It has the characteristics of multi-level control, combined control, synchronous control, reverse control, safety control, etc.

[0055] 2. The new dual-chamber back-pressure opposed suspension cylinder structure maintains a complete and simple suspension cylinder cavity structure, as well as a complete connection between the cylinder cavity and the piston rod cavity, to build a complete suspension cylinder cavity system and an independent external control loop. The suspension cylinder cavity system provides the main parameters of the suspension cylinder, and the external control loop provides the control parameters of the system. The independent suspension cylinder cavity system and external control loop structure ensure the stability and reliability of the suspension system.

[0056] 3. The pressure action area and damping flow area of ​​the suspension cylinder cavity system are the cylinder cavity area. The pressure action area and damping flow area of ​​the external control circuit are the auxiliary oil cavity area. The external control circuit and the suspension cylinder cavity system form a double-chamber counter-pressure opposing structure. In addition to compensating and correcting the defects and deficiencies of the pressure characteristics of the suspension cylinder cavity system, it also forms the bidirectional pressure characteristics and zero-crossing balance point of the suspension cylinder, and can effectively control the stroke and stiffness of the suspension cylinder. See Fig.16 , Fig.17 , Fig.18 , Fig.19 .

[0057] 4. The variable damping adaptive control in this example is based on the complete structure of the suspension cylinder cavity, as well as the complete structure and association of the relative position, speed, pressure, flow rate, etc. between the cylinder cavity and the piston rod cavity. The internal control valve group is a variable damping control mechanism based on the internal pressure of the system, which realizes dual-point, steady-state variable damping flow control. F = f(p, v). Fig.15 These are two damping characteristic curves that the system automatically matches under empty / full load conditions. The variable damping control flow area in this example is the cylinder inner cavity area, which has reached the maximum state of the cylinder structure.

[0058] The core of the internal control valve group is to build a valve core assembly and a variable damping structure with internal pressure as the control input to form an internal variable damping channel. The valve core assembly contains a closed pressure chamber for system identification, and the internal spring provides the valve core reference pressure to drive the valve core to move. The valve core reference pressure is set between the no-load pressure and the full-load pressure of the suspension cylinder. The valve core is arranged with two groups of internal / external damping holes and a one-way valve, which cooperate with the valve core seat ring to form a fixed damping channel and a controllable damping channel, and the fixed damping channel is always open. The controllable damping channel opens when the valve core is extended, and the controllable damping channel closes when the valve core is retracted. The valve core assembly also includes a damping chamber and a damping ring to control the steady-state response of the valve core itself. Fig.11 This is a detailed structural diagram of the internal control valve group.

[0059] Several points about the internal control valve group:

[0060] ①. The variable damping structure, variable damping channel and automatic control structure are constructed inside the cylinder body, and the system pressure in the suspension cylinder cavity is used as the input parameter of the variable damping control, F = f (p, v).

[0061] ②. The valve core reference pressure is used to identify the no-load pressure and full-load pressure inside the system, and is superimposed with the system pressure to push the valve core to maintain two specific positions of extension and retraction. Therefore, it is a typical two-point variable damping control, see Fig.15 .

[0062] ③. The damping chamber and damping ring in the valve core assembly are used to control the steady-state response of the valve core itself. The pressure fluctuations and pressure shocks inside the system will not cause transient start-up and rigid impact of the valve core. Therefore, the system is a steady-state control.

[0063] ④. This example is currently the only suspension cylinder structure that realizes external active control and internal variable damping automatic control based on a dual-chamber back-pressure opposed structure, providing a new basic oil-gas suspension cylinder structure for future technological development.

[0064] 5. This patent is the first to be proposed outside of existing literature and products. As an active control oil-gas suspension structure under mechanical / hydraulic control mode, it has obvious innovative characteristics and application value.

[0065] This patent The dual-channel lateral stiffness active oil-gas suspension is based on the oil-gas suspension and realizes active control of the oil-gas suspension roll stiffness in a mechanical and hydraulic manner through a specific structure and control principle. It has a good application range and use value for the existing complex and expensive electronic control active suspension system. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 Schematic diagram of the piston rod being placed upward and the single air chamber and double oil chamber structure;

[0067] Figure 2 Schematic diagram of the piston rod being placed downward and the single air chamber and double oil chamber structure;

[0068] Figure 3 Schematic diagram of the piston rod being placed upward and the single air chamber and three oil chambers structure;

[0069] Figure 4 Schematic diagram of the piston rod being placed downward and the single air chamber and three oil chambers structure;

[0070] Figure 5 Schematic diagram of the piston rod being placed downward and the single air chamber and three oil chambers structure;

[0071] Figure 6 Schematic diagram of the piston rod upwardly placed, single air chamber, three oil chambers pressure compensation structure;

[0072] Figure 7 Schematic diagram of the structure with piston rod placed downward and double air chambers connected in series with three oil chambers;

[0073] Figure 8 Schematic diagram of the structure with piston rod placed downward and double air chambers facing each other in opposite directions and three oil chambers;

[0074] Fig. 9 Schematic diagram of the structure with piston rod placed downward and double air chambers facing each other in opposite directions and three oil chambers;

[0075] Fig.10 This patent Schematic diagram of the isolated dual-chamber suspension cylinder structure;

[0076] Fig.11 This patent A magnified view of the variable damping internal control valve group structure of the suspension cylinder;

[0077] Fig.12 Stiffness characteristic curves of traditional single air chamber and tandem dual air chamber suspension cylinders;

[0078] Fig.13 The stiffness characteristic curve of the traditional dual-chamber back-pressure opposed structure suspension cylinder;

[0079] Fig.14 The damping characteristic curve of the traditional oil-gas suspension cylinder;

[0080] Fig.15 This patent Suspension cylinder pressure control variable damping characteristic curve;

[0081] Fig.16 This patent Stiffness characteristic curve of isolated dual-chamber suspension cylinder;

[0082] Fig.17 This patent External control loop stiffness control characteristic diagram;

[0083] Fig.18 This patent Suspension cylinder inner cavity system stiffness control characteristic diagram;

[0084] Fig.19 This patent Isobaric / synchronous stiffness control characteristic diagram of the external control loop and the suspension cylinder inner cavity system

[0085] Fig. 20 This patent Isolated dual-chamber suspension cylinder structure and basic system / circuit diagram;

[0086] Fig.21 This patent Structure diagram of dual-channel lateral stiffness active oil-gas suspension system;

[0087] Fig. 22 This patent Structure diagram of the left-turn system of the dual-channel lateral stiffness active hydro-pneumatic suspension;

[0088] Fig.23 This patent Dual-channel lateral stiffness active hydro-pneumatic suspension right turn system structure diagram; DETAILED DESCRIPTION

[0089] This patent, a dual-channel lateral stiffness active oil-gas suspension, adopts a left-right symmetrical layout structure, including a steering wheel 1, an angle synchronization control valve 2, a stiffness synchronization control valve 3, a suspension cylinder 8, an accumulator 15, a control valve 16, a pipeline 17, and a pipeline 18. The suspension cylinder 8 includes a piston rod 10, a piston 11, an internal control valve group 12, a cylinder barrel 13, and a sealing seat ring 14. The cylinder barrel 13, the piston rod 10, and the piston 11 form a suspension cylinder inner cavity 20 (rodless cavity) inside the suspension cylinder 8. The cylinder barrel 13, the sealing seat ring 14, the piston rod 10, and the piston 11 form a secondary oil chamber 21 (rod chamber) between the side walls of the waist of the suspension cylinder 8. The secondary oil chamber 21 is filled with hydraulic oil and is completely isolated from the suspension cylinder inner cavity 20. The suspension cylinder inner cavity 20 is divided into a cylinder barrel inner cavity 22 and a piston rod inner cavity 23 by the internal control valve group 12 at the bottom of the piston rod 10. The cylinder inner cavity 22 is filled with hydraulic oil, and the piston rod inner cavity 23 is filled with hydraulic oil and nitrogen. The cylinder inner cavity 22 and the piston rod inner cavity 23 are connected through the damping channel on the internal control valve group 12 to form a complete suspension cylinder inner cavity system 30 of the suspension cylinder 8. An external control interface 31 is provided at the bottom of the cylinder inner cavity 22. The auxiliary oil cavity 21 is provided with a connection port at a position of the cylinder 13 near the sealing seat ring 14, and is externally connected to the energy storage device 15 and the control valve 16 through the pipeline 17 to form an independent external control circuit 40 of the suspension cylinder 8. The control valve 16 is provided with an external control interface 41. The external control circuit 40 is completely isolated from the suspension cylinder inner cavity system 30 and is independent of each other. Fig. 20 The internal structure and basic system / circuit diagram of the suspension cylinder 8 are shown below. Fig.10 It is a structural diagram.

[0090] The auxiliary oil chamber 21 in the external control circuit 40 and the cylinder barrel inner chamber 22 in the suspension cylinder inner chamber system 30 form a double air chamber counter-pressure opposing structure.

[0091] The accumulator 15 is filled with hydraulic oil and nitrogen. The auxiliary oil chamber 21 serves as a target link for externally controlling the state, stroke and stiffness of the suspension cylinder. The control valve 16, in addition to serving as an input port for externally controlling the state, stroke and stiffness of the suspension cylinder, also serves as a damping / flow control element of the external control circuit 40 itself.

[0092] The internal control valve group 12 is a pressure-controlled automatic variable damping component, which is installed at the bottom of the piston rod 10. The automatic variable damping control of the suspension cylinder in the empty / full load state is realized by sensing the pressure of the suspension cylinder inner cavity system 30. Fig.11 It is a detailed structural diagram of the internal control valve group 12. Fig.15 It is the automatic variable damping control curve of the internal control valve group 12.

[0093] The angle synchronization control valve 2 is connected to the external control interface 41 of the left / right suspension cylinder external control circuit 40, forming a "state control channel" with the angle synchronization control valve 2 as the core, connecting and controlling the two external control circuits 40 of the left / right suspension cylinder. The stiffness synchronization control valve 3 is connected to the external control interface 31 of the left / right suspension cylinder suspension cylinder cavity system 30 through the pipeline 18, forming a "stiffness control channel" with the stiffness synchronization control valve 3 as the core, connecting and controlling the two suspension cylinder cavity systems 30 of the left / right suspension cylinder. The "state control channel" / "stiffness control channel" and the included external control circuit 40 / suspension cylinder cavity system 30 are independent of each other to ensure the stability and reliability of the system operation. The angle synchronization control valve 2 and the stiffness synchronization control valve 3 are synchronously controlled with the steering wheel 1.

[0094] Fig.21 This is the structural diagram of the dual-channel lateral stiffness active oil-pneumatic suspension system.

[0095] When the steering wheel 1 turns left, the angle synchronization control valve 2 inputs / outputs the control flow Q1 to the left / right external control circuit 40 respectively, the pressure of the left external control circuit 40 increases, the left accumulator 15 absorbs the flow ql, and the left auxiliary oil chamber 21 increases the flow Ql, Ql=Q1-ql, the pressure of the right external control circuit 40 decreases, the right accumulator 15 releases the flow qr, and the right auxiliary oil chamber 21 reduces the flow Qr, Qr=Q1-qr, and the chassis is controlled to produce a left roll angle. The stiffness synchronization control valve 3 inputs / outputs the control flow Q2 to the left / right suspension cylinder inner cavity system 30 respectively, so that the left suspension cylinder inner cavity system 30 reduces the flow Q2, and the right suspension cylinder inner cavity system 30 increases the flow Q2, compensating for the height change of the left / right suspension cylinder caused by the angle synchronization control valve 2 controlling the "state control channel", and controlling the chassis to increase the left roll stiffness. See Fig. 22 , system structure state diagram when turning left.

[0096] When the steering wheel 1 turns right, the angle synchronization control valve 2 inputs / outputs the control flow Q1 to the left / right external control circuit 40 respectively, the pressure of the left external control circuit 40 decreases, the left accumulator 15 releases the flow ql, and the left auxiliary oil chamber 21 reduces the flow Ql, Ql=Q1-ql, the pressure of the right external control circuit 40 increases, the right accumulator 15 absorbs the flow qr, and the right auxiliary oil chamber 21 increases the flow Qr, Qr=Q1-qr, and the chassis is controlled to produce a rightward roll angle. The stiffness synchronization control valve 3 outputs / inputs the control flow Q2 to the left / right suspension cylinder inner cavity system 30 respectively, so that the left suspension cylinder inner cavity system 30 increases the flow Q2, and the right suspension cylinder inner cavity system 30 reduces the flow Q2, compensating for the height change of the left / right suspension cylinder caused by the angle synchronization control valve 2 controlling the "state control channel", and controlling the chassis to increase the rightward roll stiffness. See Fig.23 , system structure state diagram when turning right.

[0097] When the vehicle is traveling in a straight line, the angle synchronization control valve 2 does not actively generate control flow for the left / right external control circuits 40, and there is no control flow between the stiffness synchronization control valve 3 and the left / right suspension cylinder cavity system 30. In the suspension cylinder cavity system 30, the piston rod cavity 23 and the cylinder barrel cavity 22 exchange flow through the internal control valve group 12; in the external control circuit 40, the accumulator 15 and the auxiliary oil cavity 21 exchange flow through the control valve 16. When the road is bumpy, the pressure difference generated by the left / right external control circuits 40 is cut off by the angle synchronization control valve 2; the stiffness synchronization control valve 3 contains a damping cut-off valve, and the instantaneous high pressure generated between the left / right suspension cylinder cavity systems 30 is attenuated and cut off by the stiffness synchronization control valve 3.

[0098] When the vehicle is turning, all systems and circuits are in working state. In the "state control channel", the angle synchronization control valve 2 adjusts and distributes the flow of the left / right two external control circuits 40 to achieve posture control of the chassis. In the "stiffness control channel", the stiffness synchronization control valve 3 adjusts and distributes the flow of the left / right two suspension cylinder cavity systems 30 to achieve stiffness control of the chassis and mechanical response to the "state control channel". Under the control of different steering angles of the steering wheel, the vehicle's steering angle, roll angle, and roll stiffness form a series of corresponding states, realizing active control of the roll stiffness of the suspension system.

[0099] This example The dual-channel lateral stiffness active oil-gas suspension proposed for the first time an active suspension control scheme based on the lateral stiffness of the oil-gas suspension and a new basic suspension cylinder component structure. The scheme is based on traditional mechanical hydraulic technology and abandons the complex and expensive electronic control system. It has outstanding advantages in terms of system stability, reliability, and service life. In addition, the control capacity of the system has been greatly improved, which significantly expands the scope of application and use value.

[0100] The basic suspension structure is upgraded from steel leaf spring and coil spring to oil-gas suspension, with the focus on the isolated dual-chamber suspension cylinder structure, which is a basic condition for the breakthrough of the control scheme. Another important breakthrough is the solution to the systemic problem of variable damping control of oil-gas suspension cylinder under non-electronic control conditions. As a result, the active control technology of oil-gas suspension will no longer rely on complex electronic control systems, but can achieve economical, efficient and large-capacity chassis active control by relying on classic mechanical / hydraulic principles. This example is a solution architecture for chassis active control based on travel, state and stiffness. Combining it with the currently constructed automatic variable damping control technology will greatly expand the application field and the range of vehicle models.

[0101] Previous active control technologies overly relied on electronic control systems and neglected the research on traditional structures and technologies. From the existing literature and various existing vehicle models, this structural scheme is the first to reveal the complete structural scheme of the lateral stiffness active control suspension system under non-electronic control conditions, which has obvious innovative characteristics and application value.

Claims

1. A dual-channel lateral stiffness active oil-gas suspension, adopting a bilaterally symmetrical structure, including a steering wheel, an angle synchronization control valve, a stiffness synchronization control valve, a suspension cylinder, an accumulator, a control valve and a pipeline; the suspension cylinder includes a piston rod, a piston, an internal control valve group, a cylinder barrel and a sealing seat ring; the cylinder barrel, the piston rod and the piston form a suspension cylinder inner cavity inside the suspension cylinder; the cylinder barrel, the sealing seat ring and the piston rod and the piston form a secondary oil cavity between the side walls of the waist of the suspension cylinder; the secondary oil cavity is filled with hydraulic oil and is completely isolated from the suspension cylinder inner cavity; the suspension cylinder inner cavity is divided into a cylinder and a cylinder by the internal control valve group at the bottom of the piston rod. The inner cavity of the cylinder and the inner cavity of the piston rod; the inner cavity of the cylinder is filled with hydraulic oil, and the inner cavity of the piston rod is filled with hydraulic oil and nitrogen; the inner cavity of the cylinder and the inner cavity of the piston rod are connected through the damping channel on the internal control valve group to form a complete suspension cylinder inner cavity system; an external control interface is provided at the bottom of the inner cavity of the cylinder; the auxiliary oil cavity is provided with a connection port at a position of the cylinder near the sealing seat ring, and an energy accumulator and a control valve are externally connected through a pipeline to form an independent external control loop; the control valve is provided with an external control interface; the external control loop is completely isolated from the inner cavity system of the suspension cylinder and is independent of each other; it is characterized in that: The angle synchronization control valve is respectively connected to the external control interface of the left suspension cylinder external control circuit and the external control interface of the right suspension cylinder external control circuit, forming a "state control channel" with the angle synchronization control valve as the core, connecting and controlling the left suspension cylinder external control circuit and the right suspension cylinder external control circuit; the stiffness synchronization control valve is respectively connected to the external control interface of the left suspension cylinder external control circuit and the external control interface of the right suspension cylinder external control circuit, forming a "stiffness control channel" with the stiffness synchronization control valve as the core, connecting and controlling the left suspension cylinder external control circuit and the right suspension cylinder external control circuit; the "state control channel" and the "stiffness control channel" are independent of each other; A secondary oil chamber air chamber is provided above the connecting port in the secondary oil chamber, and the secondary oil chamber air chamber is filled with gas; The angle synchronous control valve and the stiffness synchronous control valve are synchronously controlled with the steering wheel; When the vehicle is traveling in a straight line, the angle synchronization control valve and the stiffness synchronization control valve block the external control circuit of the left suspension cylinder and the external control circuit of the right suspension cylinder; when the vehicle is turning, the angle synchronization control valve and the stiffness synchronization control valve connect the external control circuit of the left suspension cylinder and the external control circuit of the right suspension cylinder; Among them, when the suspension cylinder is compressed or stretched, the volumes of the cylinder inner cavity and the auxiliary oil cavity both change, and when the volumes of the cylinder inner cavity and the auxiliary oil cavity change, the medium inside them is compressed or expanded to change the pressure, so that the auxiliary oil chamber in the external control circuit and the cylinder inner cavity in the suspension cylinder inner cavity system form a double air chamber back-pressure opposing structure.

2. The dual-channel lateral stiffness active oil-gas suspension according to claim 1, characterized in that: The internal control valve group serves as a variable damping control component between the inner cavity of the cylinder barrel and the inner cavity of the piston rod.

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